Apparatus for absorbing shock loads



March 5, 1946. J R. o. ANDERSON ETAL APPARATUS FOR ABSORBING SHOCK LOADSFiled April 14, 1945 4 Sheets-Sheet ZL March 5, 1946. R. o. ANDERSON ETAL 2,396,071

APPARATUS FOR ABSORBING snocx LOADS Filed April 14; 1943' 4 Sheets-Sheet2 R. o. ANDERSON ETAL APPARATUS FOR ABSORBING SHOCK LOADS March 5 1946.

Filed April 14 1943 4 Sheets-Sheet 3 M s, 1946,, R; 5; ANDERSON Em.2,396, 1

APPARATUS FOR ABSORBING SHOCK LOADS Filed April 14, 1943 4 Sheets-Sheet4 Patented Mar. 5, 1946 teem arraaa'rus roa aasoanmo snoox LOADS.Rexford dry, Tulsa, Okla., and Wallace F. Ardussi,

said Ardussi assignor to Foote Bros.

cago. 11L:

; Anderson, Chicago. 111., Max E. Lan- Chl- Gear and MachineCorporation, Chicago, 111., a

corporation of Delaware Application April 14, 1943, Serial panama v .10Claims.

This invention relates to apparatus for absorbing shock loads and moreparticularly to apparatus for smoothly and evenly picking up astationary load with a moving vehicle or for bringing a moving vehicleto rest.

The invention is particularly described herein in connection with anapparatus for picking up gliders by an airplane but it will beunderstood that it is equally useful to bring a moving plane to rest orabsorb, other similarly produced shock loads. In picking up gliders andparticularly relatively large. gliders, it is necessary that theaccelerating force be applied evenly and smoothly to avoid damage to theplane or glider and shock to the occupants. The present invention hasfor '15 one of its principal objects the provision of apparatus forabsorbing sudden shock loads of this type in which the'force howevermade efiective is applied gradually and smoothly from a zero value ofthis force absorption can be varied to suitany specific application.

Another object of the apparatus for absorbing shock loads inwhich-the avelocity. substantially equal to the relative velocity between thepickup and load at the time of connection. According to one importantfeature paratus may be driven at the desired velocity and clutched tothe reel thereof to drive it.

- to the maximum value required. The time cycle '20 invention 'lstoprovide of the invention, the velocity of the pickup ap-' Another objectof the invention is to rovide apparatus for absorbing shock loads inwhich the device for driving the pickup to neutralize its inertiaeifectis controlled by completion of the 40 connection between the pickup andload. In one desirable arrangement a hook is used to connectthe pickupand load and the driving device is controlled by the hook.

"Still another object of the a braking force is'graduallyandprogressively lappalled to the pickup after it is connected to the Afurther object of the invention is to provide A still furtheroblect ofthe invention is to provide apparatus for absorbing shock loads in whichapplication of the brake force is controlled by the amount of cableremaining on the pickup reel.

I The above and other objects and advantages of the invention-will bemore readily apparent from .the following description when read inconnection with the accompanying drawings, in which- Figure 1 is adiagrammatic view indicating use of the invention to pick up a glider byan airlane; i D Figure 2 is a top plan view oi the pickupmechanism; s

Figure 3 is a diagrammatic section illustrating the connections betweenthe parts of Figure 2;

'- Figure 4 is a side view of a hook with parts in section;

Figure 5 is a partially enlargedx section on the line 5--5 of Figuremechanism;

Figures 6 and 7 are partially enlarged sections on the lines 6-6 and 1-1respectively of Figure 2 showing the brake control mechanism; andFigures Band 9' are diagrammatic sections sim-' inertia of the rotatingmass of the pickup 3p- 5v ilartoFigure 3 showing alternativeconstructions.- p aratus is neutralized by giving the apparatus 1 inwhich a pickup device is carried by an airplane III to pick up a gliderit while the airplane is in flight. For this purpose, the airplane isprovided with a rod .l2 projecting from its under surface and detachablycarrying at its outerend a grappling hook l3. The hook I3 is connectedby a cable to a reel [4 in the airplane.

The glider is connected to a tow cable l5 terminating at'its' end in aloop I6 supported on masts ll. To pick up the glider the plane I0 isflown over the loop at such an altitude that the hook I! will engage theloop and detach it from the masts H. The hook l3 will at the same time,be detached from the rod l2 so that cable on the reel M will pay out ata gradually decelerating speed to pick up gradually the glider load.

invention is to pro- 4 vide a, device-for absorbing shock loads in whichAfter a relatively short interval, the reel l4 may be gradually andfully braked so that the glider will be connected directly to, the towplane through the cable on the reel and the tow cable l5.

, One apparatus for controlling the reel in the planeis shown in Figures2 and 3 comprising a frame l8 adapted to be rigidly mounted in the planeand rotatably carrying avreel l9 on which cable 2| is wound. The reel issupported in bearings in posts 22 on the frame and is connected at oneend to the outer housing 23 of a hydraulic transmission which may be ofthe type more particularly described and claimed in the patent 2 showingthe brake operating 'iustably connected by a to Carson and Anderson, No.2,150,539, issued March 14, 1939. The housing 23 carries sets of vanes24 at its sides between which there is mounted a vaned rotor member 25cooperating with the vanes 24 to form a double liquid circuit. The rotormember 25 is drivably connected to a shaft 25 extending through the hubof the reel l9 and connected at the other side of the reel to the sungear 21'0f a planetary differential gear unit. This unit includes a ringgear 28 carried by a'housing 29 which is connected to the reel and sets01' planet pinions 3| on a carrier 32.

The carrier 32 of the gear set is connected to a brake drum 33, having abrake band 34 engage'able with it to hold the brake drum sta tionary anda similar brake drum 35 is formed on the housing 23 of the hydraulictransmission through which it is connected directly to the reel. A brakeband 36 cooperates with the drum 35 to hold it stationary whendesired.

The brake bands 34 and 36 are controlled through a mechanism illustratedmore particularly in Figure 5 to apply ing force. As shown in Figure 5,this mechanism comprises a bracket 31 connected to one end of. v theband 36. A link 38 is pivoted at one end to the bracket and carries atits other end a block 39 sliding in an arcuate slot 4| in a lever 42which is pivoted at 43 to a second lever 44 fixedly pivoted at nectedthrough a link 46 to the opposite end of the band 36 and the outerend oflever 42 is adbolt 41 to the free end of lever 44.

The bracket 31 is adjustablyiconnected to one end ofa tension spring 48which passes around a pulley 49 and has its opposite end connected tothe block 39. The mechanism is controlled by rocking the link 38 througha link 5| conneeted to arm 52 on a pivot 53. When the shaft 45. TheDivot connection 43 is cona progressively increas 53 1s turnedcounterclockwise to its extreme position the block 39 will lie in theright end of slot 4| to produce a leverage ratio between the two ends ofthe brake greater than the wrap ratio of the brake so the brake willrelease as more fully described in the patent to Carson and Anderson No.2,116,013. As the shaft 53 turns clockwise the block 39 will be moved tothe left to vary the leverage ratio between the two ends of the brakeband until it becomes less than the wrap ratio so that the band becomesprogresssively more and more self-energizing and its braking effect onthe drum gradually increases. When the block 39 finally reaches the leftend of the 'slot 4| as shown in Figure 5 the leverage ratio will be suchas to lock the brake positively to prevent any further rotation of thedrum. The mechanism for controlling the band 34 is similar and will notbe described in detail.

Engagement of both of the brakes is controlled in accordancewith thediameter of the cable 2! on the reel l9 to cause their progressiveapplication as the diameter decreases. For this purpose the brake 34 iscontrolled by a follower roller 54 engaging .the cable on the reel andsupported by a bracket 55 mounted on the frame adjacent the reel.pivoted on the bracket 55 and is urged into engament with the cable by aspring 51. The lever 56 has an extending arm 58 connected through anadjustable link 59 with an arm 6| secured to a shaft 62.- The shaft 62connects to the brake actuating mechanism for the band 34 andcorresponds to the shaft 53 shown. in Figure 5. With this construction,when the reel is full of cable -er roller 63 engaging the cable on thereel and carried by a lever 64 pivoted on a bracket 65. A spring 66holds the follower 63 in engagement with the cable. The lever 64 asshown in Figure 6 carries an extension 61 formed on one side with anarcuate surface 68 terminating adjacent one end in internal gear teeth69. The teeth 69 are adapted to mesh with gear teeth on a segment Hkeyed to the shaft 53, a roller being carried by the end tooth H to rideonthe surface 68. A spring 12 On the segment 7| engages the surface 68and tends to rock the segment in a direction to engage the roller in thefirst tooth with surface 68 and later with the teeth 69.

With this construction, when the reel is sub stantially full of cable,the lever 64 will be rocked to a position to bring the arcuate surface68 opposite the segment 1|. As the lever turns in response to areduction in diameter or the cable on the-reel, the extension 61 will beturned toward the position shown'in Figure 6. Toward the end of thismovement, the segment 1| will engage the gear teeth 69 to turn thesegment and the shaft 53 and engage the brake 36. By properlypositioning the teeth 69 on the extension, it will be seen that thebrake 36 can be engaged at any desired time subsequent to the engagementof the brake 34. This brake. serves as a safety device to preventwithdrawal of all of the cable from the reel I final braking force tostop completely the rotation of the reel.

As shown in Figure 2, the cable may be rewound on the reel by a motor 13connected through gearing 14 and a clutch 15 to gear teeth 16 formed onone flange of the reel. When the motor 13 is operating and the clutch l5engaged the reel will be turned in a direction to wind the cable'thereoneither for rewinding purposes or for shortening the distance between thetow plane and the glider. A hand crank 11 may be connected to one end ofthe shaft 26 to permit manual rewinding if desired.

In picking up relatively heavy loads it will be apparent that theinertia of the reel and its associated parts would be sufficient tocause a rather severe shock at the time of connection of the cable tothe load. In order to eliminate this condition, means are providedaccording to the present invention to drive the reel in a direction tounwind cable therefrom at a speed substantially equal. to the relativevelocity between the tow plane and the load. As shown in Figure b 2,this is accomplished by providing an expansion exhausting through asimilar conduit 84. The

' breech assembly may be controlled electrically The roller 54 iscarried by a lever 56 through wires and is adapted to hold and fire iThe breech assembly and motor a cartridge. form a known type ofcartridge actuated engine starting device and will not be described indetail herein. This mechanism operates when the circuit through wires 85is energized to fire a cartridge in the breech assembly so that highpressure fluid charge of relative short duration will be supplied to themotor 18. In response and also provides the engagement with the load.

to this charge the motor will move the clutch l9 into engagement withthe'clutch 8| and will then 'drive the clutch 8| and thereel assemblywith an extremely high torque to accelerate it to the desired veldcityin a very short interval of time. This construction isparticularlyadvantageous since is light in weight and occupies a smallspace and enables the reel to be accelerated rapidly without unwinding alarge amount of cable therefrom.

The accelerating motor is controlled by conpurpose a hook as shown inFigure 4 may be employed. The hook is detachably connected to the rod l2'and is held assembled thereon by a spring urged keeper 86. When thekeeper is in the position shown to hold the hook on the rod l2-it opensa switch 81 carried by the rod. When,

however, the hook engages a loop l6 the keeper will .be pressed down todisconnect the hook from the rod [2 and at the same time to release theswitch 8l so that it may close. The switch 81 is connected in circuitwith the wires 85 so that when it closes a cartridge in the breechassembly 82 willbe fired.- The hook as shown and described is moreparticularly described -and claimed inthe copending application toRexford nection of the cable to the load and for this 'O. Anderson,Serial No. 481,711, filed April 3,-

1943, now' Patent No. 2,359,275, dated September 26,1944. t I Inoperation of this apparatus the breech mechanism}! is loaded with acartridge and the hook i3 is supported on the end of the rod l2 as shownin Figures 1 and 4. When the tow plane flies .pver a glider to be pickedup the book will engage the loop 16 moving the keeper 88 back againstthespring and permittingthe switch 81' to close. When this occurs thecartridge in thebreech mechanism will be fired to actuate the motor" sothatthe reel and its I associated parts .will'jbedriven at a speedtoumwind the cable from the reel at substantially the same velocity asthat of the tow plane. I when the cable engages the loop the cable willThus bepaid out from the reel 'atsubstantially the same-rate as therateyof travel of the plane so that no shock will occur at the time ofinitial As the cable is unwound, from the reel due to operation of thedriving motor and the pull of the load on the cable the diameter of thecable on the reel will decrease so that the follower roller 54 will turnthe shaft 82 gradually and progressively to engage the brake drum 34.This will hold the gear carrier 32 againstrotation so that as the reelturns it will turn the ringgear and through the idler pinions 3! willturn the I sun gearzl and' shaft 26 in the reverse direction.

" This will/turn'the rotor memberv in reverse and at the same time'thecasing 23 of 'reel so that therelative velocity between the two parts ofthehydraulic transmission will be mag-t nifled. Thus the rotation of the'reel is resisted through the hydraulic transmission so that a 1smoothand gradual braking force is applied to becomes fully engaged. Att-tmsttime, thegllder' is travellingatthesame speed' as the tow planeand may be towediat: the emzltof that cable'ror, if?

desired; may be drawn-closer" to; ti ler-tow plane 1 collar 96haying'clutch; teeth-:on-kits end? for, en-- gagement withcomplementary: clutch teeth =91 formed on one. hub ofithe free].Theat-wo clutches are controlled, ibywai slidingaco'llar iillawhlchimay:be operatedv bya yoke, :89. under. the,v controllof" a solenoid, in 1.When [the solenoid a is-energized the collar 98: willimoyeqto thearight' flrst itoeengage, the clutch, 94; andtthereafater to-=bringthe.-: c-lutchteeth 96' into engagement withzithe teeth 91;

, At the opposite;- end oftthe-reel" the: shaft =95; iskeyedorsplinedi'to asleeve; l'lllion whichiatcenten 'gear I03 and, a variedhydraulic. rotor aliMiaremounted. The' rotor- M14 cooperateswith: vanes:

formed in a .fiuid: transmission housing; .lilli'tandf.

which isconnectedtowa ring; gear 105;. The-tsungear I03 and the-ringgearwslillil mesh-.mthqplaneta l08.- At one end the:shaft:iisformed with;

driving. means shown as a. pulley itllfi whichimay; be driven througha;tbeltvfromanydesinedttype; of motor. i

In operation of this unitswithttheflclutches 5914 and 96 disengagedas,.:shown, thesha-ftflzmay be driven through the pulley lil.9'.-torotate-.:thehy-- draulic transmission I :and; the gearing; as a unit.When the hook onthejcable engages aiload av circuit will be completedthroughlthessolenoidrtlli.

to engage the clutch -9J.4.-=therebyf connecting"the;-

shaft .95 to the reeL, TheFiner-tie:offithe-tsevemlz rotating partswillfbeetransmltted i o 'thei'flreel'j to accelerate it rapidly to avelocltysubstantlally. equal to that of the tow plane but incoppositedirection so that the load may be, engaged without shock. Thereafter thebrake drum I08, may' be braked by mechanism similar to that shown inFigures '1 to 7' to cause relative rotation between the transmissionparts. I04 and lll5:gradu-.- ally and smoothlyto resist rotation of thereel. Finally the brake 92 may be engaged tobringjthe reel to a completestop-as described above.

' Figure 9 illustrates a somewhatsimpllfledform v of invention which isbetter adapted to the pick slow the rotation of the reel and to increasethe speed of the glider. i

As cable continues to be withdrawn the follower roller 63 will'turn theshaft 53 to the point where the gear teeth 69 turn the segment llgradually to apply the brake 36. The braking force of this brake willbeadded to the hydraulic braking effect to slow the reel still further andfinally to bring it to a full stop as the brake 36 1 directiyi 60. thetr, nsmission will be turned forward by the up of lighter'loads. Inthisconstruction, a frame ill rotatably supports a reel H12 formed at oneend with a brake flange. H3. The reel 112' is supported on and keyedtoatshaft :l'l4terminat- 1 ing at one end in-ya clutchsmember .Hikforconnecting it to a driving devicesuch as the expansion motorshownintFigure '2.

At the other end the shaft I I4: is keyeduto as 1 vaned'rotor member 8enclosed in a.v vaned housing ill to form a hydraulic transmission.Thehousing ill carriesabrakenrum'zliiili In theoperatlon of this unitvafter the load-has:

been engaged thebrake :H 8v may be.- enga d hold the casing 'I I1stationary. Rotation of -the reel causes the rotor HGto turn in thehousing H'lto apply a braking force-m'rotatlon-of thereel. As cablecontinues to. bewithdrawnqfrom.

the reel, the brake lliwill be-engaged tobrin;

The reel isconn'ected :at oneend :to-a clutch; V 7 housing 93"carrying;v a clutch. plate for: engasement 'withclutch plates ..9'4;keye.d :or. splinedto; a center shaft :35; The-shaft :alsoicarries :a.:clutch" on the end of the cable for' connecting it to'a the reel to afull stop. Thus the operation of thisconstruction is substantially. the,same as those described above except that a lesser degree of relativerotation isprovided between the coupling'parts. j

While severalembodiment's of the invention ,have been shownand'described in detail, it will on the; end of the cable for connectingit to a load,.means to drive the reel in a; direction to unwind cabletherefrom, control means to inltiate operation of the last named meanswhen the, cable is connected to the load, a brake connected to the reel,and control means for the brake to cable for connecting it to the load,an expansion motor, means connecting the expansion motor to the reel todrive the reel in a direction to unwind .cable therefrom, a breechassembl adapted to containand fire a cartridge connected 'to theexpansion motor to deliver a high pressure charge offluid of shortduration to the motor, electrical means to fire a cartridge in thebreech assembly,

and a control switch for'the electrical means operated by engagement ofsaid means on the cable witha load.

7. Apparatus for absorbing shock loads comprising a reel, a cable on thereel, means on the cable to connect it to a load, a hydraulic transcauseit to engage subsequent to the operation of the means for driving thereel.

'2. Apparatus for absorbing shock loads comprising a reel, a cable woundon the reel, means load, a fluid transmission having one elementconnected to the reel, a brake connected to the other element of thefluid transmission, a brake connected to the reel, means to drive thereel in a direction to unwind cable therefrom, control means operable inresponse to connection of the cable to a load to initiate operation ofthe last named means, and control means for the brakesoperable'subsequent to the reel drive means to engage the first namedbrake and then to engage the last'named brake.

3. Apparatus for absorbing shock loads comprising a reel,- 9. cablewound onthe reel, means on the .end of the cable for connecting it to aload, a; fluid coupling having one element connected to'the reel, abrake connected-to the other element of'the fluid coupling, a brakeconnected to the reel, means to drive the reel in a direction to unwindcable therefrom, control means operable in response to connection of thecable to a load to initiate operation of the last named means, andcontrol means for the brakes responsive t0 the diameter of the cable onthe reel to engage the first named brake and thereafter to engage thelast named brake.

4. Apparatus for absorbing shock loads com end of the cable forconnecting it to a load, power means for driving the reel in a directionto unwind cable therefrom, and means on the hook operated by engagementthereof with aload to initiate operation of the power means.

5. Apparatus for absorbing'shock loads comprising a reel, a cable on thereel, means on the cable for connecting it to a load, an expansionmotor, means connecting the expansion motor to the reel to drive thereel in a direction to'unwind cable therefrom, a breech assembly adaptedprising a reel, a cable on the reel, a hook on the mission, meansconnecting one part or the transmission to the reel, difierentialgearing, means connectionof the cable to a load to fire a car-v tridg'ein the breech assembly.

8. Apparatus for absorbing shock loads comprising a reel, a cable onthereel, meam on the cable to connect-it to a load, a hydraulictransmission, means connecting one part of the transmission to-the.reel, differential gearing, means connecting two elements of thegearing to two parts of the transmission respectively, a brake to.

hold a third element of the gearing, a second brake connected directlyto the reel, control means for the brakes responsive to the diameter ofthe cable 'on the reel initially to hold the brakes disengaged, powermeans for driving the reel in a direction to unwind cable therefrom, andcontrol .means for the power means to initiate its operation in responseto connection of the cable to a load, the brake control means operatingas the cable diameter on the reel decreases to engage the'first namedbrake and thereafter to engage the second brake. I

9. Apparatus for absorbing shock loads comprising a reel, a cable on thereel, means to connect the cable to a load, power means to drive -thereel in a direction to unwind cable thereprising a reel, a cable on thereel, means to conto contain and fire a cartridge connected to the Jexpansion motor to deliver a high pressure charge of fluid ofshortduration to the motor, and con-- trol means operated by connection ofthe cable to a load to fire, a cartridge in the breech assemy.

6. Apparatus for absorbing shock loads. comprising a reel, a cable onthe reel, means on the,

nect the cable to a load, power means to drive the reel in a directionto unwind cable therefrom, hydraulic means connected to the reel toresist rotation thereof in response to a load on the cable, meansoperable in response to connection of the cable to a load to initiateoperation of the power means, and control means for the hydraulic meansto make it effective after operation of the power means.

REXFORD O. ANDERSON.

MAX E. LANDRY. WALLACE F. ARDUSSI.

